The internet is obsessed with mouth taping at night. What horrifying side effect are they trying to stop?

The problem people hope to quiet is snoring

Mouth taping is meant to keep the lips closed during sleep, encouraging a person to breathe through the nose instead. The immediate targets are usually mouth breathing and snoring—and the dry mouth that can follow a night spent breathing through an open mouth. That dry feeling can also make morning breath more noticeable.

Snoring happens when airflow makes relaxed tissues in the back of the throat vibrate. Breathing through the nose may reduce the open-mouth airflow that contributes to some snoring, but it cannot fix every cause. A blocked nose, for example, can make nasal breathing difficult in the first place.

Snoring can be a clue, not just a nuisance

Loud, persistent snoring can sometimes accompany obstructive sleep apnea, a condition in which the upper airway repeatedly narrows or closes during sleep, interrupting breathing. Mouth tape does not remove that obstruction or treat apnea. In some people, especially those with nasal congestion or an airway problem, sealing the mouth may make breathing harder.

So the alarming concern behind the trend is often the possibility that snoring signals a more serious breathing problem. But taping the mouth is not a reliable way to prevent that problem; it can also conceal a symptom worth paying attention to. The key distinction is whether someone is simply waking with a dry mouth—or repeatedly struggling to breathe during sleep.